Rapidly dissolving

Succinamide. NHoCOCH2 CH2CONH2. (Method 2(a)). Add 5 ml. (5 8 g.) of dimethyl succinate to a mixture of 50 ml. of water and 25 ml. of concentrated [dy o-88o) aqueous ammonia solution in a 150 ml. conical flask. Cork the flask and shake the contents the dimethyl succinate rapidly dissolves to give a clear solution. Allow the solution to stand after about i hour the succinamide starts to crystallise, and then continues to separate for some time. Next day, filter off the succinamide at the pump, wash with cold water, and drain. Recrystallise from water, from which the succinamide separates as colourless crystals the latter soften at 240° and melt at 254 -255° with... 

Place 30 ml. of ethanol in a 200 ml. conical flask fitted to a reflux water-condenser, and then add 1-4 g. of sodium cut into small pieces. The sodium rapidly dissolves to give a solution of sodium ethoxide, the ethanol boiling under the heat of the reaction. When the sodium has completely dissolved, detach the flask and cool it in ice-water. 

At a pH above about 9, in the presence of sodium carbonate or sodium hydroxide, for example, the protective oxide layer is rapidly dissolved and corrosion becomes severe (Fig. 8.1). Aluminum in the presence of sodium hydroxide corrodes as in Reaction 8.2 ... 

The crude naphthoquinone is warmed gendy on the steam bath with 1.5 1. of ether, when it rapidly dissolves and leaves in suspension a slight amount of dark, fluffy material. The solution... 

For many applications, the main need is for agglomerated particles having an open particulate array which rapidly dissolves (as in some pharmaceuticals), while in others a more dense structure is required giving a slow release of its components (as in fertilizers). 

The resulting acid vapors have a great affinity for water (do you remember how rapidly HC1 dissolved in water in the film, gases and how they combine ). Hence the HBr rapidly dissolves in water and concentrations as high as 0.5 Af can be reached, a thousandfold more concentrated than original sea water. With this concentration, chlorine is again introduced to produce Br2 by reaction (20). 

Parcopa with phenylalanine) Rapid-dissolving LD as symptoms increase, use 200 mg LD tab 2-4 times daily usual MD is... 

Zelapar with phenylalanine) Rapid-dissolving selegiline Start with 1.25 mg every morning before breakfast if symptoms continue after 6 weeks, increase dose to 2.5 mg every morning. Avoid food or liquid for 5 minutes before or after the dose... 

Use rapid-dissolving tablet (Parcopa ), crush Sinemet , or make liquid Sinemet ... 

Substitute or add rapid-dissolving tablet form or liquid form of Sinemet ... 

The most common extravascular route is oral. When a solution or a rapidly dissolving solid dosage form is given orally, the absorption process often obeys first-order kinetics. In these cases, absorption can be characterized by evaluating the absorption rate constant, ka, using plasma concentration versus time data. 

A retained its compact capsule shape no matter what the initial pH of the dissolution medium. Moreover, the dissolution rate of phenytoin from preparation A was pH-independent. Preparation B, however, broke down into fine particles. When the initial pH was neutral, these particles rapidly dissolved. As the initial pH was lowered, these fine particles precipitated. Since these precipitated particles then dissolved very slowly, it would appear that the precipitate was not the freely soluble sodium phenytoin, but the poorly soluble acid form of phenytoin. Since capsule A did not disintegrate or deaggregate, most of the sodium phenytoin was not exposed to the lower pH media and, as a result, was not converted to its very slowly dissolving acid form. 

Hard shell capsules have often been assumed to have better bioavailability than tablets. Most likely this assumption derives from the fact the gelatin shell rapidly dissolves and ruptures, which affords at least the potential for rapid release of the drug, together with the lack of utilization of a compaction process comparable to tablet compression in filling the capsules. However, capsules can be just as easily malformulated as tablets. A number of cases of bioavailability problems with capsules have been reported [5-8],... 

FIGURE 44 Weathering. A weathered sandstone column. Calcite (composed of calcium carbonate) is dissolved by rain and groundwater (see Textbox 73). When stone in which calcite is a main component as, for example, sandstone, limestone, and marble, is in contact with water for long periods of time, it is weathered and partly or entirely dissolved. Pollutants such as sulfur dioxide are fundamental in accelerating the weathering and dissolution process. When sulfur dioxide, for example, dissolves in rainwater, it forms sulfuric acid, a strong acid that, at ambient temperatures, rapidly dissolves calcium carbonate. 

For prophylaxis when undertaking activities that predictably precipitate attacks, nitroglycerin 0.3 to 0.4 mg sublingually may be used about 5 minutes prior to the time of the activity. Nitroglycerin spray may be useful when inadequate saliva is produced to rapidly dissolve sublingual nitroglycerin or if a patient has difficulty opening the tablet container. The response usually lasts about 30 minutes. 

If the process is reversed and the flow-rate increased, the system evolves smoothly from A1 to C on a stable branch. At C, the excess heat brought in by a large input of fluid is no longer balanced by the output and is suddenly converted into latent heat. The system thaws . A large fraction of solid is rapidly dissolved up to D where the system joins a stable branch. 

The FDA currently allows biowaivers (27) (drug product approval without having to show bioequivalence in vivo) for formulations that contain Class I drugs and can demonstrate appropriate in vitro dissolution (rapidly dissolving). 

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